I have two Deco Ax5400 units and three P9 units in my home. While my ISP router delivers 750-900 Mbps, the Deco system provides only 25 Mbps to an Ethernet-connected PC on the first floor and on the top floor I'm getting 15min to wifi devices. Despite turning off QoS and switching to 5GHz, I'm unable to improve the speed. The main Ax5400 Deco is ocated on the ground floor and has a P9 in the room next to it, just 10-15 feet away, but the speed drops to 130 Mbps in that room.

I'm really starting to consider running Ethernet cables to give me consistent speeds as nothing seems to get my speeds up. 
 

Any advice is appreciated